Young Johnny is gung-ho and full of courage. Johnny's brainiac twin sisters, Susan and Mary, use Johnny as their guinea pig for their outrageous scientific experiments. If they can dream it up, Johnny will do it; as long as his genetically engineered super dog, Dukey, can come along.
James Arnold Taylor
as Johnny Test (voice)
Maryke Hendrikse
as Susan Test (voice)
Ashleigh Ball
as Mary Test (voice)
Lee Tockar
as The General / Bling-Bling Boy (voice)
Ian James Corlett
as Hugh Test (voice)
Trevor Devall
as Dukey (voice)
Kathleen Barr
as Lila Test (voice)
Scott McNeil
as Mr. White / Bumper (voice)
Bill Mondy
as Mr. Black (voice)
